Getting Started with your CGM
If you’re like me, you want to know what to expect. That’s why we documented our experience with unboxing the Freestyle Libre CGM and applying it!
Once you activate the sensory, it will take an hour before it is ready to start scanning. I also had about a 2 hour “warm up” period where my readings were very low and inaccurate (something I confirmed with a glucometer and good old fashioned finger pricks). However, it did start reading accurately for the rest of the 2 week trial period.
As you embark on this journey, it is good to understand that you WILL observe glucose spikes. I know I did! I put myself to the test and saw my highest spikes when I ate a breakfast bar, when I ate a bowl of ice cream on an empty stomach, and when I had an Acai bowl for lunch. The ice cream we know isn’t great, but I was surprised that such a low calorie breakfast bar would spike me. The Acai bowl didn’t surprise me, but since this is touted as a “health food” or “super food” I could see where someone may eat those frequently because of that, not realizing how much sugar they actually contain. I also observed that eating out caused my glucose to spike which is most likely due to the hidden sweeteners in dressing or sauce that you don’t realize.
I saw a cause and effect that I expected. Your glucose should spike when you eat something high in carbohydrates and sugar. It should also come back down to your pre meal values less than 2 hours later - which mine always did! My average daily glucose was also 98 with the goal being to stay <100mg/dL. I found my highest average was between 12-3pm at 105mg/dL and my lowest average was between 9pm-6am at 92mg/dL. I also found that I needed to spread out my carbohydrate intact when doing my long runs (I did a half marathon distance and took in 1 packet of Skratch gummies before and 1 packet at the 8 miles mark) and saw some major spikes and dips. I found spreading out my fueling helped to reduce the large fluctuations.
The above image is from Blood Sugar Battles of what a diabetic CGM reading may look like. You can see that glucose is always above 100, rises past 250 after meals, and takes more than 2 hours to get back to the pre-meal level.
Here is a summary of what we want to see on a CGM:
Key numbers include:
First morning glucose reading: less than 100mg/dL
Pre meal glucose: less than 100mg/dL
After eating, the goal is to not have glucose go over 130-140mg/dL
Less than 2 hours post meal, your glucose should be less than 100mg/dL
Night time glucose should remain stable. Dips and spikes can cause insomnia or night time waking due to the adrenaline rush that follows a glucose dip.